ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
SOIL AIR CONTENT EFFECTS ON THE WATER STATUS OF AVOCADO TREES |
| Authors: | R. Ferreyra, P. Maldonado, J. Celedón, P.M. Gil, A. Torres, G. G.Selles |
| Keywords: | aeration, avocado, stomatal conductance, stem water potential |
| Abstract:
Avocado trees evolved in Andisoils, which are considered the optimum type of soils for tree growth due to their physical properties; mainly low bulk density (0.5 – 0.8 g cm-3) and high macro porosity (~ 46%). In Chile, avocado orchards are mostly located in fine textured soils, with bulk densities between 1.3 and 1.5 g cm-3 and macro porosities close to 15%. Due to this fact, there are severe problems of poor root aeration which, in part, are responsible for the low production levels of the crop. The objective of this research was to study the effect of soil aeration in the root zone on avocado water status. The ultimate goal of this study was to generate information for developing irrigation management strategies for avocado orchards that optimize the air and water contents in the soil. The study was conducted during the 2004/05 season. Two-year-old avocado var. 'Hass' on Mexicola root stock were planted in 50 L pots using four soils of different texture. The treatments were T0: loam soil; T1: sandy soil; T2: sandy loam soil; T3: clay loam soil. Soil air content between 5% and 18% affected stomatal conductance, but not stem water potential. Soil air content lower than 17% restricted the oxygen diffusion rate to less than 20 μg cm-2 min-1, the threshold value for normal avocado tree development. | |
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